US4815136A
Expired / Lapsed
US
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Voiceband signal classification
Assignee: Nokia Bell Labs
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Filing: 1986-11-06
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Granted: 1989-03-21
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Expires: 2006-11-06
Abstract
Abstract A signal is classified as one among a plurality of classifications by employing the autocorrelation of a complex low-pass version of the signal, i.e., the complex autocorrelation. The normalized magnitude of the complex autocorrelation obtained at a prescribed delay interval, i.e., "lag", is compared to predetermined threshold values to classify the signal as having one of a plurality of baud rates.
Inventors
- 👤 Nevio Benvenuto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:26
CPC Classifications
H; H04; H04L; H04L7/00; H04B; H04B14/00; H04B14/02; H04B14/04; H04L27/00; H04L27/32; H04L27/34
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
49 words
Apparatus for classifying a signal comprising, means for generating a complex low-pass version of an incoming signal, means for generating an autocorrelation of said complex low-pass version of said incoming signal, and means for utilizing said autocorrelation to classify said incoming signal as one of a plurality of classifications.
Claim 2
Dependent Claim
49 words
Apparatus for classifying a signal comprising, means for generating a complex low-pass version of an incoming signal, means for generating an autocorrelation of said complex low-pass version of said incoming signal, and means for utilizing said autocorrelation to classify said incoming signal as one of a plurality of classifications.
Claim 3
Dependent Claim
20 words
The apparatus as defined in claim 1 wherein said means for generating generates said autocorrelation at a prescribed delay interval.
Claim 4
Dependent Claim
35 words
The apparatus as defined in claim 2 wherein said incoming signal is a digital signal sample having a predetermined sample interval and wherein said prescribed delay interval is a predetermined number of said sample intervals.
Claim 5
Dependent Claim
17 words
The apparatus as defined in claim 3 wherein said predetermined number of sample intervals is two (2).
Claim 6
Dependent Claim
38 words
The apparatus as defined in claim 2 wherein said means for generating includes means for generating a first prescribed characteristic of said autocorrelation and said means for utilizing uses said first prescribed characteristic to classify said incoming signal.
Claim 7
Dependent Claim
20 words
The apparatus as defined in claim 5 wherein said first prescribed characteristic is related to the magnitude of said autocorrelation.
Claim 8
Dependent Claim
41 words
The apparatus as defined in claim 5 wherein said first prescribed characteristic is the magnitude of said autocorrelation and wherein said means for generating said first characteristic includes means for normalizing said first characteristic by a second characteristic of said autocorrelation.
Claim 9
Dependent Claim
26 words
The apparatus as defined in claim 7 wherein said means for normalizing generates said second characteristic which is respresentative of the power of said incoming signal.
Claim 10
Dependent Claim
20 words
The apparatus as defined in claim 8 wherein said second characteristic is representative of said autocorrelation at zero (0) delay.
Claim 11
Dependent Claim
39 words
The apparatus as defined in claim 9 wherein said means for utilizing includes means for comparing said normalized magnitude of said autocorrelation with predetermined threshold levels to classify said incoming signal as one of a plurality of baud rates.
Claim 12
Dependent Claim
35 words
The apparatus as defined in claim 10 wherein said incoming signal is a digital signal sample having a predetermined sample interval and wherein said prescribed delay interval is a predetermined number of said sample intervals.
Claim 13
Dependent Claim
14 words
The apparatus as defined in claim 11 wherein said predetermined number is two (2).
Claim 14
Independent Claim
47 words
A method of classifying a signal comprising the steps of, generating a complex low-pass version of an incoming signal, generating an autocorrelation of said complex low-pass version of said incoming signal, and utilizing said autocorrelation to classify said incoming signal as one of a plurality of classifications.
Claim 15
Independent Claim
47 words
A method of classifying a signal comprising the steps of, generating a complex low-pass version of an incoming signal, generating an autocorrelation of said complex low-pass version of said incoming signal, and utilizing said autocorrelation to classify said incoming signal as one of a plurality of classifications.
Claim 16
Dependent Claim
27 words
The method as defined in claim 11 wherein the step of generating the autocorrelation generates a first prescribed characteristic representative of the normalized magnitude of the autocorrelation.
Claim 17
Dependent Claim
36 words
The method as defined in claim 12 wherein the step of utilizing compares the normalized magnitude of the autocorrelation with predetermined threshold levels to classify the incoming signal as one of a plurality of baud rates.
Claim 18
Dependent Claim
32 words
The method as defined in claim 13 wherein the first prescribed characteristic is generated by normalizing the magnitude of the autocorrelation by a value representative of the power of the incoming signal.
Claim 19
Dependent Claim
40 words
The method as defined in claim 14 wherein the incoming signal is a digital signal sample having a predetermined sample interval and the autocorrelation is generated at a prescribed delay interval equal to a predetermined number of the sample intervals.
Claim 20
Dependent Claim
17 words
The method as defined in claim 15 wherein the predetermined number of sample intervals is two (2).
References Cited (Backward Citations)
US4297533A
Cited
US4281218A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |